Nov 01 1999: New research finds that Web shopping tools currently being integrated by retailers to improve the online shopping experience may do more harm than good when many will fail to work this season.   A survey from Computer Economics, an independent market research firm, concludes that slow download times and poor performance will discourage consumers from shopping online again. Among the new features which claim to enhance the consumer experience are 3D clothes models, live customer service and communal chat areas where consumers can talk to one another.   The study found that the majority of 3D models tested were painfully slow to download and did not simulate the real experience of trying on clothes. Chat rooms, where consumers were told they could talk to each other while shopping, quickly became clogged up and did not work in tandem with surfing. Meanwhile, many of the shop assistants offered poor customer service as they were not familiar with the web site.   According to Catherine Huneke, senior research analyst with Computer Economics, it may be too late for retailers to do anything about this, "New features will be added quickly in the next few weeks, but the bugs will not have been smoothed out before crowds of customers come to the sites."